The American Food and Drug Administration (FDA) has rejected an application for accelerated approval of CNM-Au8, an experimental drug for Amyotrophic Lateral Sclerosis (ALS), announced the drug manufacturer Clene Nanomedicine today. The agency concluded that the initial data from the company’s clinical Phase 2 study program did not provide sufficient evidence of reduction in Neurofilament Light Chain (NfL), a key biomarker of neurodegeneration.
CNM-Au8 consists of catalytically active gold nanocrystals that can bypass the blood-brain barrier and target the energy production of brain cells to promote remyelination. The company claims that CNM-Au8 is not associated with toxicities commonly seen with other synthetic gold compounds.
As previously reported by Medscape Medical News, the drug did not meet the primary outcome of the Phase 2 RESCUE-ALS study, which was to show a change in the summated motor unit index (MUNIX) after 36 weeks. However, the company stated that the drug is safe and reported significant efficacy after 12 weeks.
In a separate statement released today, the company reported results from a 12-month open-label extension of the treatment arm in the HEALEY ALS Platform Trial. Researchers observed a 16% decrease in plasma NfL after 76 weeks of treatment compared to placebo. The company also reported that the treatment group had a 60% lower risk of long-term mortality. These results have not been peer-reviewed.
The drug is also being investigated for the treatment of Parkinson’s disease and Multiple Sclerosis.
The FDA did not comment on the rejection of Clene’s approval. An FDA spokesperson stated that the agency is „generally unable to discuss existing or potential applications as they are confidential business information.“
The company plans to provide additional data to the FDA in early 2024, according to the statement.
Kelli Whitlock Burton is a reporter for Medscape Medical News and covers neurology and psychiatry.